Process fob improving drying



Oct. 18 1938. 'T. S.HQDGINS I 2,133,894

PROCESS FOR IMPROVING DRYING PROPERTIES OF OILS Filed Feb. 26, 1937 8 Sheets-Sheet l %ALKAL|NE .5

NEUTRAL .2 %ACID TIME OF GE.LAT\0N (HOURS) v DNDEX REFRACTIOH TIME grvu c toc ZdWOW 9% Wjme Oct. 18, 1938. T. s. HODGINS 2,133,894

7 PROCESS FOR IMPROVING DRYING PROPERTIES OF OILS Filed Feb. 26, 1&3? 8 Sheets-Sheet 2 CURVES: MAXIMUM ALKAu-KMnm AND ACID KM" %ALKAL! O- I O I NEUTRAL OJO aa yuym Oct. 18, 1938. T s, HQDGINS 2,133,894

PROCESS FOR IMPROVING DRYING PROPERTIES OF OILS Filed Feb. 26, 1957 8 Sheets- Sheet 5 OXIDATION CURVES OF UNTREA SOYA BEAN OIL Gum/mm Oct. 18, 1938. T. s. HODGINS Filed Feb. 26, 1957 ALKALl-PERMANGANATE SAMPLES GELATiON PNROVZNG DRYING PROPERTIES OF OILS 8 Sheets-Sheet 4 amen for Oct. 18, 1938. T, s, HODQNS 2,133,894

PROCESS FOR IMPROVING DRYING PROPERTIES OF OILS Filed Feb. 26, 1937 8 Sheets-Sheet 5 COMPARISON 6F KOH KM" AND KM O HCI TREATMENTS 5.0.

TIME l5 THE TIME TO COMPLETE GELATION %ACI 0 OR 7ALKALI HC' KMnO4 TREATMENT 0Z0 0 4Q 1343 00 I20 \60 200 220 240 HOURS Gum/MA;

Oct. 18, 1938. HODGlNs 2,133,894

PROCESS FOR IMPROVING DRYING PROPERTIES OF OILS Filed Feb. 26, 1957 8 Sheets-Sheet e AClD PERMANGANATE SAMPLES SAMPLE %ACID %KM O GELATION l N HOURS O'O25 50 0.05 60 0.20 68 0-50 88 O- 75 I00 I .00 H2 MW yyjwa,

Oct. 18, 1938. T. s. HO'DGINS PROCESS FOR IMPROVING DRYING PROPERTIES OF OILS Fild Feb. 26, 1937 HNO5 TREATED SAMPLES SAMPLE asuno eamyonflas) 8 Sheets-Sheet 7 PROCESS FOR IMPROVING DRYING PROPERTIES OF OILS Filed Feb. 26, 1937 8 Shets-Sheet s COMPARISON CURVES OF LINSEED OlL. TREATED, AND UNTREATED TED SOYA OIL INDUC ON IO 40 5o I00 no 4 flwmmhm Patented Oct; 18, 1938 UNITED STATES' PATENT OFFICE 2,133,894 v raooass FOR maovnvc. DRYING- PROPERTIES OF OILS Theodore S. Hodgins, Detroit, Mich., assignor to Helmuth Beichhold, doing business as Reichhold Chemicals, Detroit, Mich.

Application February 26, 19?], Serial No. 127,971

'3 Claims.

- This invention relates to a process for improving the drying properties of raw oils by removing anti-oxidants therefrom, so as to render the oils more suitable for use in the paint and kindred industries.

I am aware that previous attempts have been made to improve the drying properties oi oils by partially oxidizing the same, particularly by passing air or other oxidizing gas through the.

body of theoil. My invention is not concerned with this type of oxidation. .In such prior procasses the oxidation has taken place within the' successful process has been carried out wherein the anti-oxidants are removed by treatment at room temperature with an oxidizing agent and with controlled acidity or controlled alkalinity with respect to the oil. 3 According to my process I regulate the acidity or alkalinity of'the treating solution, maintaining avalue only slightly on the acid or slightly on the alkaline side. I find that atithe neutral point (pH of 7.0) it is impossible to efiectively treat the oil for the purpose herein set forth, and

also if the acidity. or alkalinity exceeds a certain predetermined limit which varies only slightly according tothe type of oxidizing agent employed, the process becomes less and less effective until a point is reached where substantially no improvement occurs. Accordingly my process consists in treating the oils witha relatively strong oxidizing agent in low concentration with respect to the oil,-and within predetermined limits on the acid or alkaline side.

The length of time required for treating-these ,oils is determined by the first measurable incrase in refractive index or by a corresponding decreaseiniodine number. The method of treatment of an oil comprises treating the oil preferably at roomtemperature either with an aqueous solution of oxidizing agents such as perman'- ganates, chromates, nitric acid and the like, or with organic oxidizing agents such as peroxides winanalcoholicalkalinesolutionoranaqueous soya bean oils treated with alkali-permanganate acid solution may be employed within the limited alkaline or acid range to be more fully described hereinafter. This process effectively removes the anti-oxidants (such as lecithin and 'kephalin) which are naturally occurring in these oils. 'ljhe 5 sludge containing the anti-oxidants and spent reagents may be separated from the refined oil in. any suitable manner, such as filtering or centrifuging, depending on the nature of the treat; ing solution. In the case of alcoholic solutions 10 the excess alcohol may be removed by distillation. I have determined by numerous experiments the optimum of acid or. alkaline values and this will be more apparent from a consideration of I the'accompanying graphs, in which:

' Fig. 1 is ageneral graph showing the relation between the acidity or alkalinity and the time of elation in hours. 7

Fig. 2 is a general graph showing the conditions for'determining the length of time of treatment. 20

Fig. 3 is a specific graph showing the eflect of regulated quantities ofalkali and acid in the presence of a constant amount of potassium permanganate in an aqueous solution.

Fig. 4 is a graph showing the'rate of drying of 25 a representative group of untreated soya bean oils.

- Fig. 5 is a graph showing the rate of drying of reagents.

' Fig. 6.is a graph showing the comparative efiectiveness of various percentages of acid or 'alkali on the total drying time of oils treated with various reagents.

Fig. '7 is a graph showing the rate of dryingof 35 oils treated with acid-permanganate reagents.

Fig. 8 is a graph showing the rate of dryingof will be noted however that the rate of diflusion is greater in the alkali process than in the acidthe case of alkali and downward for acid, it will be noted that increasing amounts 'of acid or alkaliexert'arepressive eflectonthereaction'.

Excessive amounts slow down the reaction to sub stantially zero.

Since the anti-oxidant is an amino compound (lecithin or kephalin) it forms salts with the acids. These salts of the acid and amino compounds are more stable than the amino compounds and therefore harder to break down or decompose. With this thought in mind it is evident that the alkali will be more effective than the acid treatment.- Experiments have shown this to be the case, the maximum acid concentration based on the percent of acid per 100 parts of oil being about two times the maximum alkali concentration, 1. e., about two times more acid than alkali is required to obtain the maximum on the acid side than is required on the alkaline side. This relation applies only to the case of a process employing inorganic oxidizing agents in aqueous solution.

The optimum treating conditions using an inorganic oxidizing agent may be summarized as mhws- Alkali treatment Per cent Alkali-(K011) 0.025 KMnO; 1.0 Water (not constant). 1.0-10

Time of treatment-5&4 hours. Product. -An oil slightly lighter than the original in color, and which goes to complete gelation in 25 hours.

. Acid treatment Per cent 01 0.05 KMnOr 1.0 Water (not constant) 1.0-10

1 between the range of .02 to .50. The preierred range for the acid treatment is from .025 to .050

as indicated by the lower graph forming partof Fig. 3.

While in most of the above graphs soya bean' oil was treated, comparable results. are obtained using other drying or semi-drying oils such as linseed oil, sun flower oil, perilla oil, rape seed oil and oiticica oil,'the variation in the graphs using these other oils being of an order of plus orv minus 5% of the values indicated in the graph.

\ In the above graphs, the aqueous solution of an .inorganic oxidizing agent was employed.

While the optimum point for oxidizing agents is expressed as 1.0%, comparable results can be obtained using the range from 0.5 to 1.5 parts of oxidizing agent by-weight per parts of oil.

The invention will be furtherapparent from the following specific examples which are intended as illustrative only and not as in any way limiting the invention: I V

Example 1 Partsby weight Soya bean oil 100' Potassium permanganate, 1 Potassium hydroxide .025

Water (not constant) 1.0-10

ing means and does not in any way enter into the reaction; This mixture is agitated from 1 to 2 hours preferably at substantially room temperature and thedecomposed impurities filtered out.

The exact time of treatment depends on how soon the anti-oxidant is destroyed.- The complete destruction of anti-oxidants is determined when the refractive index (Fig. 2) first begins to increase. (The correlation between the index of refractionand iodine number was first established by A. M. Wagnet and J. C. Brier (Ind. Eng. Chem., p. 40, Jan. 1931).) The resultant oil is much improved in dryingproperties and has a slightly lighter color. A film of this treated oil when baked one hour at 200 F. proves to be harder than the best refined linseed oil subjected to the same bake.

Example 2 Using the above agitation time and tempei'a ture as described in Example 1, this process yields an oil slightly lighter in color than the original and possessing the same improved drying properties referred to in Example 1.

Example 3 Parts by weight Oiticica nil 7 100 Sodium dichromate 1.5 Frm 0.3

Water (not constant) 1.0-10

The operating conditions may be described'in Examples 1 and '2 and the final product possesses similar characteristics.

Example 4 Parts by weight Raw linseed oil 100 Sodium dichromate 1.5 Sodium hydroxide 0.3 Water (not constant) 1.0-10

Same agitation is in the preceding examples which results in an oil with improved drying" properties as described in Examples 1 and 2. I

While particular oils have been referred to in 55 the preceding examples it will be understood that various other-oils may be substituted with similarly improved drying properties in the final product.

I claim: 1. A process for improving the drying quality of raw\oils containing naturally occurring antioxidants, which comprises removing the antioxidants from such oils by treating. the oils, at substantially room temperature with a relatively 6 strong inorganic oxidizing agent in concentra- .--tion of 5-1.5 parts of oxidizing agent per 100 of the acid falling within the range of .025-.050 part by weight or acid to 100 parts by weight 01' the oil.

2. A process for improving the drying quality of raw oils containing naturally occurring antioxidants, which comprises removing the antioxidants from .such oils by treating the oils at substantially room temperature with a relatively strong inorganic oxidizing agent in concentration of 5-15 parts of oxidizing agent per 100 parts by weight of the oil, and maintaining the pH value close to the neutral point while avoiding exact neutrality by treating the oil with an alkaline reagent, the proportion of the alkaline reagent employed falling within the range of .013-.050 part by weight of alkali to 100 parts by weight of the oil being treated.

3. A-process for improving the drying quality of raw oils containing naturally occurring antioxidants, which comprises' removing the antioxidants from such oils by treating the oils at substantially room temperature with a relatively strong inorganic oxidizing agent in concentration 01 .5-1.5 parts of oxidizing agent per 100 parts by weight of the oil, and maintaining the pH value close to the neutral point while avoiding exact neutrality by treating the oil with an acid, the proportion of the acid employed falling within the range of .020-.050'part by weight of acid to 100 parts by weight of the 011 being 

